Randomized Comparison of Cladribine Single (C) or in Combination with Cyclophosphamide (CC), and COP in Previously Untreated Low Grade B-Cell Non-Hodgkin Lymphoma Patients.

To comparatively assess first-line treatment with cladribine single (C) or in combination with cyclophosphamide (CC), and COP (cyclophosphamide, vincristine, prednisone) in low grade B-cell non-Hodgkin lymphoma (NHL), previously untreated patients (pts) with Ann Arbor stage II-IV were randomly allocated to receive 6 monthly courses of either C, CC, or COP. End points were treatment response, freedom from progression (FFP) and overall survival (OS), and tolerance. From June 1, 2000 to June 30, 2005, 196 pts were randomized in 17 centers. Of 153 pts for whom data is available, 55 (36%) were diagnosed as small lymphocytic, 11 lymphoplasmocytoid (7%), 37 marginal-zone (24%), 42 follicular (27.5%), and 8 not otherwise specified low grade B-cell NHL (5.5%). Randomization constituted comparable groups, including International Prognostic Index variables. Compared to C and CC, COP induced lower overall response rates (75%, 90%, 50%, χ² =7.9 p<.005), including lower complete remission rates (38%, 62%, 9.5%, χ²=19.2 p<.0001). With a median follow-up of 15 months, FFP was superior in patients receiving cladribine-containing regimens (χ² = 21.8, log-rank p<.0001). No difference in median OS was observed. Incidences of infections (9% versus 3.5% versus 7%) and non-hematological side effects (7.5% versus 3.5% versus 7%) were similar in the randomized groups, whereas CC but not C induced more frequent peripheral cytopenias compared to COP (30% versus 11%, p=.034). This resulted in higher frequency of prolongation of intervals between CC versus COP treated pts (respectively 45% and 21%, χ²=6.04 p=.014) and C versus CC treated pts (respectively 26% and 45%, χ²⁼4.24, p=.039). Dose reductions because of hematological or other toxicity were comparable in C (9.5%), CC (20%), and COP (21%) groups. Although final results warrant completed data for all randomised pts with longer follow-up, similar tolerance and higher efficacy of cladribine-based regimens over COP provide rationale to combine C or CC with rituximab in future clinical trials.